The present invention relates to an electronic wristwatch and more particularly relates to a switch mechanism for an electronic wristwatch for controlling an operation mode of the watch.
The electronic wristwatch usually includes a digital display unit made of, for example, a liquid crystal display unit or light-emitting diodes. The light-emitting diodes consume considerably large power, though it is not preferable for an electronic wristwatch. In order to avoid unnecessary power dissipation on the light-emitting diodes, an effective display system has been proposed wherein the display is enabled only at a desired time by closing a switch of which a knob is provided on a frame of the wristwatch. It was difficult to handle the above-mentioned switch of the prior art, since the knob was very small and the wristwatch can not always be tightly fixed to the operator's wrist. The vacuum-tight construction was complicated because of provision of such switch knob.
Accordingly, an object of the present invention is to provide a novel switch mechanism for an electronic wristwatch for controlling an operation mode of the electronic wristwatch.
Another object of the present invention is to provide a network for detecting a closing of a switch mechanism of the electronic wristwatch.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description give hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objectives, pursuant to the present invention, a thin-film transparent electrode is provided on the front window of an electronic wristwatch through use of the vacuum evaporation technology. A metal frame provided at the back of the wristwatch is kept in contact with the operator's wrist in an operative condition. A complementary metal oxide semiconductor inverter circuit is provided to detect a resistance value between the thin-film transparent electrode and the metal frame. When the operator touches the thin-film transparent electrode, an electric current flow is created through the operator. The reduction of the resistance value is detected by the complementary metal oxide semiconductor inverter circuit, which then provides a signal for controlling an operation mode of the electronic wristwatch, for example, a display condition.